The goal of this study is to develop methodology which can be used to determine how the regional distribution of the weight women gain during gestation affects fetal growth and body habitus. Since radiologic methods are contraindicated in pregnancy, we will evaluate the accuracy of skinfold calliper and ultrasound measurements of regional adiposity. This data is needed to elucidate the physiologic mechanisms underlying age-related differences in optimal maternal weight gain and to establish national nutritional guidelines for pregnant adolescents.